Many well-known mods make it easier to break blocks (hammers, quarries, veinminer), but not many focus on placing them. Even the most experienced players still often place blocks one by one. This mod makes building easier by providing tools like mirrors, arrays, build modes and a block randomizer.

Mirror blocks in realtime
Build repeated sections quickly using arrays
Place random blocks using the Randomizer Bag
Quickly replace existing blocks (toggle with a key press)
All of the above works in synergy
Works in survival and creative mode

Switch build modes by holding ALT.

Build Modes

Hold ALT to switch build modes. On the left side there are buttons for undo/redo, opening the modifier settings and toggling QuickReplace (see below). On the right side there are options for each build mode, like a filled vs hollow wall, or faster building in Normal+.

Build modes:

Normal: vanilla placement
Normal+: increased reach
Line: place lines of blocks in any 3 axis
Wall: place walls with locked x or z axis
Floor: place 'walls' with locked y axis
Diagonal Line: place freeform lines of blocks
Diagonal Wall: place walls at any angle
Slope Floor: place slopes at any angle
Cube: place cubes with 3 clicks
Circle: place blocks in a circle (ellipse)
Cylinder: place a cylindrical shape like a tower
Sphere: place a spheroid made of cubes

Holding ALT is compatible with the radial menu of Chisels and Bits; when a chisel or bit is held, it will open the Chisels and Bits menu, otherwise the build mode menu.

Build Modifiers

Open modifier settings with the + key on the numpad, or click the button in the ALT menu.

Build modifiers:

Mirror
Array
Radial Mirror

Mirror

Mirror blocks in realtime, as you place them. Works with even and uneven builds (add .5 to the position). Rotates blocks like stairs, logs, slabs, pistons etc properly.

Set position, radius (size) and what axes to mirror by pressing the + key on the numpad.

Mirror settings:

Mirror settings

Position: where the mirror is situated in the world
Direction: what axes to mirror, can mirror on all axes simultaneously
Size (radius): how many blocks away from the position the mirror will still work. Limited by your reach.
Set to current pos: set the mirror's position to the current player position
Toggle odd/even: set position to center or corner of block, for odd or even numbered builds
Show lines and area: helps visualize where the mirror is

Still not sure what's going on? Watch this tutorial by ScottoMotto: The Fastest Way to Build a House in Minecraft

Array

The array modifier copies your build in a certain direction a certain number of times. Very useful for nether tunnels but also useful for quickly building walls etc.

It is possible to add offset to multiple directions so diagonal builds are possible (e.g. a nether tunnel that goes upwards or sideways). And of course breaking blocks is also supported for if you make a mistake.

Set offset and count by pressing the + key on the numpad.

Array settings:

Array settings

Offset: in what direction to replicate your block. Example: with offset (2,1,0) and count 3, placing a block at (0,0,0) will also place blocks at (2,1,0), (4,2,0) and (6,3,0).
Count: how many times to replicate your block
Reach: limits how far away you can place blocks (highest offset * count)

Radial Mirror

The radial array lets you place blocks in a circle around a certain point. The circle can be divided into slices, and each slide will copy your block placements.

I heard you liked mirrors, so I put mirrors in your radial mirror. Mirror every other slice by enabling alternative mode.

Set position, slices, radius and alternative mode by pressing the + key on the numpad.

Radial mirror settings:

Radial mirror settings

Position: center of the radial mirror
Slices: the amount of slices to cut the circle in. Each slice copies your block placements.
Radius: how many blocks away from the position the radial mirror will still work. Limited by your reach.
Alternate: mirrors every second slice

Randomizer Bag

Put blocks in the bag, then rightclick to place a random block from the bag. Adjust ratios by filling slots with the same block (e.g. 2 slots cobble + 1 slot stone makes for a 2:1 ratio). Handy for building walls and paths with variation. Combine with array and QuickReplace for super easy path building.

Crafting recipe:

Craft by surrounding any wooden planks with leather.

Randomizer Bag recipe

Survival-friendly

Playing this mod in survival mode is fully supported. When playing in survival mode:

All actions consume the right amount of blocks.
You have to use the appropriate tool to break blocks.
This correctly damages the tool based on how many blocks are broken.
Replacing only works on blocks that can be harvested by hand (changeable in config).
Mining speed is increased for each additional block mined (change percentage in config).

Explanation video:

Recommended: use Magic Feather to get flight while building.

QuickReplace

Press the - (minus) key on the numpad to toggle QuickReplace (or click the button in the ALT menu). When on, new blocks you place won't be put on the block you are looking at, but replace it. Handy for swapping out floors or replacing materials in general.

Note: in survival mode QuickReplace only works with blocks that can be harvested by hand. You can change this setting in the config.

Reach

Your reach determines how far away you can place blocks. It also determines the maximum radius of the mirror and the reach of the array.

Increase your reach using craftable reach upgrades. They need to be used in order, it is not possible to skip straight to upgrade 3 without using 1 and 2.

Reach Upgrade 1

Block placing: 12 blocks

Mirror radius: 25 blocks

Array reach: 50 blocks

Reach Upgrade 1 recipe

Reach Upgrade 2

Block placing: 25 blocks

Mirror radius: 50 blocks

Array reach: 100 blocks

Reach Upgrade 2 recipe

Reach Upgrade 3

Block placing: 50 blocks

Mirror radius: 100 blocks

Array reach: 200 blocks

Reach Upgrade 3 recipe

Miscellaneous

Toggle between creative and survival mode by pressing a key. By default not bound, I recommend binding it to F4 if you want to use it.

FAQ

"Can I add this mod to my modpack?"

Yes.

"Is this a client-side only mod?"

No, it needs to be installed on both server and client. The server part places all the blocks and verifies the players input.

"Am I allowed to make my own version of this mod?"

Yes, as long as you comply with the LGPL-3.0 license (usually this means: link to this page, license your modification under LGPL-3.0, make the code visible and state significant changes).

Mod Spotlights

ScottoMotto

Credits

Radial Menu from Chisels and Bits by AlgorithmX2

Build Modes inspired by Linear by Tschipp

Effortless Building